/* Qilin - a Java Pointer Analysis Framework
 * Copyright (C) 2021-2030 Qilin developers
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3.0 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 *
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * <https://www.gnu.org/licenses/lgpl-3.0.en.html>.
 */

package qilin.util;

import java.util.Timer;
import java.util.TimerTask;
import oshi.SystemInfo;
import oshi.software.os.OSProcess;
import oshi.software.os.OperatingSystem;

public class MemoryWatcher extends Timer {
  private final long pid;
  private final String name;
  private final long[] maxMemory;

  public MemoryWatcher(long pid, String name) {
    this.pid = pid;
    this.name = name;
    this.maxMemory = new long[1];
  }

  private TimerTask task;

  public void start() {
    this.maxMemory[0] = 0;
    task =
        new TimerTask() {
          @Override
          public void run() {
            SystemInfo si = new SystemInfo();
            OperatingSystem os = si.getOperatingSystem();
            OSProcess process = os.getProcess((int) pid);
            long mem = process.getResidentSetSize();
            if (mem > maxMemory[0]) {
              maxMemory[0] = mem;
            }
          }
        };
    schedule(task, 0, 100);
  }

  public void stop() {
    task.cancel();
    this.cancel();
  }

  public double inKiloByte() {
    return maxMemory[0] / 1024.0;
  }

  public double inMegaByte() {
    return maxMemory[0] / (1024.0 * 1024.0);
  }

  public double inGigaByte() {
    return maxMemory[0] / (1024.0 * 1024.0 * 1024.0);
  }

  @Override
  public String toString() {
    return String.format("%s consumed memory: %.2f MB", this.name, this.inMegaByte());
  }
}
